Starch native wheat

Figure 8.6 Variation in glass transition temperature of starch (DSC data) as a function of water content 1, 2 and 4 correspond to gelatinized potato, rice and wheat starch 3 and 5 correspond to amorphous amylopectin and granular wheat starch, respectively. Inset shows the DSC traces of native wheat starch at...

The amylose of native wheat starch granules consists of lipid-complexed amylose11 and lipid-free amylose.195 Lipid-free amylose and lipid-complexed amylose represent... 

Compared to native wheat starch, the sodium starch 1-octenylsuccinate derivative gives much higher peak and cold-paste viscosities, but with considerably reduced paste viscosity during the cooking cycle.27 This product also exhibits emulsifying properties. When the 1-octenylsuccinate derivative is complexed with aluminum ion, a modified wheat starch that flows freely when dry and resists wetting by water... 

Addition of 3% potato starch or a combination of potato starch and potato flour produced frankfurters that were comparable to those being successfully marketed that contained wheat starch.582 Native wheat starch and its acetylated distarch phosphate and hydroxypropyl distarch phosphate derivatives, when incorporated at a level of 3.5%, reduced cooking loss and firmness of low fat, high added water sausages cooked to 70°C or 80°C.583... 

The following matrices were employed pol)winylpyrrolydone (PVP) of molecular weight 34,000 obtained from ISP Technologies, Inc. (Wa)me, NJ) a mixture (2 1 (w/w)) of PVP gelatinized wheat starch a mixture (2 1 (w/w)) of PVP native wheat starch a mixture (3 1 (w/w)) of lactose obtained from Mallinckrodt Chemical Works (St Louis, MO) gelatinized wheat starch and gelatinized wheat starch and lactose. 

FIGURE 16.5 Glass transition temperature Tg as a function of mass fraction of water i/rw, for some substances (indicated near the curves starch means native wheat starch). 

Commercial low-extraction wheat flour was received from Swissmill (Zurich, CH). Native wheat starch was supplied by Blattmann Cerestar (Wadenswil, CH). A thermostable a-amylase (BAN, specific activity 256 KNU/g) and a maltogenic a-amylase (Novamyl, 1500 MANU/g) were received from Novozymes (Bags-ward, DK). The two enzymes have a temperature optimum of 60 to 80°C and 45 to 75 °C, respectively. Hereafter, the enzymes are referred to as a-amylase and maltogenic a-amylase, respectively. 

The crystalline precipitate, as synthesised, shows in X-ray wide angle powder diffraction which is equivalent to the B-structure of native potato starch. Upon heating in the presence of 18% by weight of water the crystallites transform to the A-structure of native wheat starch. 

Figure 26.8 Native wheat starch (a) microscopic image (b) SEM image.

Agarose-gel filtration has been used to estimate the molecular-weight distribution of native wheat starch and some oxidation products thereof. Cations bound to the phosphate groups of potato starch have been extracted with mineral acids and then determined by atomic absorption spectroscopy. ... 

Resistant starch (RS2 and RS4) 454- pyrosequencing with 16 S rRNA tagged primers 30 g RS Double-blind, crossover, controlled (native wheat starch) RS4 (chemically modified resistant starch) Actinobacteria (bifidobacteria) t, Bacteroidetes (Parabacteroides distonis) t, RS2 (native granular resistant starch), Ruminococcus bromii ] and Euhacterale rectale ] Martinez et al. ... 

FIG. 10 Gelatinization and specific heat change of native wheat starch (water solution of 40% dry matter). Instrument Setaram Micro-DSC. (Adapted from Ref. 69.)... 

Gel of native potato starch (50% DM) Gel of native wheat starch (50% DM]... 

Acetylated wheat distarch phosphate pastes had improved clarity and better storage stability than the pastes of unmodified and crosslinked alone starches when 1% aqueous dispersions were heated in a boiling water bath for 30 minutes and stored at two different temperatures (4°C and 25°C) for 9 days.27 Storage at 4°C of 5% pastes of native and crosslinked wheat starch revealed that both were unstable after one day, the soft texture of the initial pastes being transformed into an opaque and rigid gel that exhibited syneresis. In contrast, the acetylated distarch phosphate was stable for at least... 

Monophosphorylation pastes made from starch monophosphates also have greater clarity, viscosity and stability than unmodified starches,64 but are sensitive to salts, especially polyvalent cations.65 Variability in residual ash can lead to variability in the viscosity of monophosphorylated starches. Monophosphate substitution also lowers the gelatinization temperature at 0.07 DS, a value much greater than is found in food starches, the gelatinization temperature is below room temperature. Native potato starch contains 0.07 to 0.09% bound phosphorus and wheat starch contains 0.055% phosphoms, primarily as phosphoglycerides in the latter case. The FDA allows up to 0.4% phosphate as phosphoms.58 Monophosphates were used commercially in the US until about 1970. 

Greenwell, P., Evers, A. D., Gough, B. M., and Russell, P. L. 1985. Amyloglucose-catalysed erosion of native, surface-modified and chlorine-treated wheat starch granules The influence of surface protein. J. Cereal Sci. 3, 279-293. 

A separate problem is presented by starch that contains fatty acids (lipids) for instance, maize, rice, and wheat starch. The naturally occurring lipids form inclusion complexes vnth amylose that exhibit texture and morphology different from those of native starch granules. These differences are reflected by the behavior of starch at a relatively low temperature for instance, gelatinization at — 120 °. The process involved is a high-temperature retrogradation, with participation of the proton dissociated from the com-plexed fatty acid residue. A Cjj acid complexed in the helical structure of... 

Assume that you want to develop a crispy breakfast cereal in the form of flakes in which the main component is wheat starch. To start with, you use the simplest model system of native starch and water. How would you proceed, and in particular what should be the course of water content and temperature to obtain a product with the desired physical properties Tip Also consult Section 6.6.2. 

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